[Physiological characterization of the maize tropical cultivars in Venezuela] | Caracterizacion fisiologica de cultivares tropicales de maiz en Venezuela
1997
Cabrera de Bisbal, E. | Nunez, M.C. | San Vicente, F.M.
Nitrogen is one of the factors that frequently limits maize production in tropical areas. As a result, large quantities of nitrogenous fertilizer must be applied as a basic input in order to achieve satisfactory yields in the region. Nevertheless, it is difficult to sustain this crop management system over the long run, given the high costs of fertilizers. A study was undertaken of 15 tropical cultivars derived from the CENIAP-FONAIAP-Venezuela Maize Program to characterize a range of morpho-physiological traits associated with optimal and zero N use, thus obtaining basic information about the genetic potential of elite germplasm from the Venezuelan national program. The following traits were evaluated: biomass accumulation; specific foliar area; chlorophyll content; nitrogen reductase activity (ANR); and N absorption. Significant differences were detected (P 0.05) among the cultivars for ANR and chlorophyll content. Under conditions of low N, the variation was between 1.6 and 7.1 mmol h-1 g-1 and 0.55 and mg g-1 Of ANR and chlorophyll, respectively, whereas under conditions of high N the variations were between 3.3 and 16.8 mmol h-1 g-1 and 1.17 and 2.53 mg g-1, respectively. The coefficient of correlation between ANR and biomass was r
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